Ultra long pulsed dye laser device for treatment of ectatic vessels and method therefor

Abstract

A long pulsed dye laser device for selective photothermolysis comprises at least two pulsed dye lasers, such as flash lamp excited dye lasers, each generating corresponding pulsed laser beams successively in time. These laser can be coordinated by a synchronizer that sequentially triggers the lasers. A combining network merges the pulse laser beams into a combined beam and a delivery system conveys the combined pulse laser beam to a patient. An example of a delivery device is a single optical fiber. This invention enables production of the necessary pulse widths, on the order of 2 msec, which can not be achieved by individual dye lasers, generally lower than 0.8 msec. Also disclosed is a selective photothermolysis method. This method comprises irradiating a tissue section of a patient with a pulsed laser beam having a changing color across a time period of the pulse. This pulse color is selected to maximize absorption in a target tissue of a patient in response to heating caused by a preceding portion of the pulse.

What is claimed is:  
     
       1. A method for generating a long effective laser pulse for selective photothermolysis, therapy comprising: 
       generating multiple laser pulses;  
       generating a combined pulse from the multiple pulses, selecting a color of a subsequent one of the laser pulses in the combined pulse to maximize absorption in a target tissue of a patient in response to heating caused by a preceding one of the laser pulses in the combined laser pulse, the combined pulse having an effective pulse width greater than the laser pulses individually; and  
       delivering the combined pulse to a patient through a delivery system.